Support change search direction

lib/reline/line_editor.rb

@@ -1196,6 +1196,7 @@ class Reline::LineEditor
       loop do
         key = Fiber.yield(search_word)
         search_again = false
+        change_direction = false
         case key
         when -1 # determined
           Reline.last_incremental_search = search_word
@@ -1207,7 +1208,11 @@ class Reline::LineEditor
             search_word = grapheme_clusters.join
           end
         when "\C-r".ord, "\C-s".ord
-          search_again = true if prev_search_key == key
+          if prev_search_key == key
+            search_again = true
+          else
+            change_direction = true
+          end
           prev_search_key = key
         else
           multibyte_buf << key
@@ -1229,11 +1234,20 @@ class Reline::LineEditor
               case prev_search_key
               when "\C-r".ord
                 history_pointer_base = 0
+                if change_direction
+                  history = Reline::HISTORY[0..@history_pointer]
+                else
                   history = Reline::HISTORY[0..(@history_pointer - 1)]
+                end
               when "\C-s".ord
+                if change_direction
+                  history_pointer_base = @history_pointer
+                  history = Reline::HISTORY[(@history_pointer)..-1]
+                else
                   history_pointer_base = @history_pointer + 1
                   history = Reline::HISTORY[(@history_pointer + 1)..-1]
                 end
+              end
             else
               history_pointer_base = 0
               history = Reline::HISTORY
@@ -1242,11 +1256,20 @@ class Reline::LineEditor
             case prev_search_key
             when "\C-r".ord
               history_pointer_base = 0
+              if change_direction
                 history = Reline::HISTORY[0..@history_pointer]
+              else
+                history = Reline::HISTORY[0..@history_pointer]
+              end
             when "\C-s".ord
+              if change_direction
+                history_pointer_base = @history_pointer
+                history = Reline::HISTORY[(@history_pointer - 1)..-1]
+              else
                 history_pointer_base = @history_pointer
                 history = Reline::HISTORY[@history_pointer..-1]
               end
+            end
           else
             history_pointer_base = 0
             history = Reline::HISTORY

test/reline/test_key_actor_emacs.rb

@@ -1620,6 +1620,70 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     assert_cursor_max(0)
   end
 
+  def test_search_history_front_and_back
+    Reline::HISTORY.concat([
+      '1235', # old
+      '12aa',
+      '1234' # new
+    ])
+    assert_line('')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s12")
+    assert_line('1235')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0) # doesn't determine yet
+    input_keys("\C-s")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r")
+    assert_line('1235')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+  end
+
+  def test_search_history_back_and_front
+    Reline::HISTORY.concat([
+      '1235', # old
+      '12aa',
+      '1234' # new
+    ])
+    assert_line('')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r12")
+    assert_line('1234')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0) # doesn't determine yet
+    input_keys("\C-r")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s")
+    assert_line('1234')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+  end
+
   def test_search_history_to_back_in_the_middle_of_histories
     Reline::HISTORY.concat([
       '1235', # old